Primary Prevention of Heterotopic Ossifications After Total Hip Replacement: Electromyotomy Technique

Abstract

We compared the benefit of modification in surgical technique in relation to primary prophylaxis of heterotopic ossifications after total hip replacement with straight stem. This modification contains the so-called electromyotomy technique and was compared versus standard „cold blade“ technique. Two groups were assessed and matched by BMI, sex, age and arthrosis type undergoing hip replacement. Traumatic, dysplastic and rheumatic hips were excluded. A total of 682 patients were evaluated, 262 cemented, 402 uncemented and 18 hybrid types with minimum of 1 year follow-up (average 5.6 years). The standard “sharp blade” technique contained 313 hips, the alternative contained 369 hips. Surgeries were performed according to the same protocols and by one team via anterolateral approach. Patients with risk factors for heterotopical ossifications and administration of secondary prophylaxis modalities were excluded. The development of heterotopic ossification were assessed with blind control of radiologic specialists (Brooker´s grades). Heterotopic ossification (HO) developed in 32.69%, totally in 223 patients. Of those clinically relevant (Brooker III and IV grades) were 8.94%, in 61 patients. In standard group there were 137 HO in 313 hips (43.76%), clinically relevant in 12.78%, 40 patients. In this group there were 123 cemented hips with 53 HO, 174 uncemented with 74 HO and 16 hybrid prostheses with 10 HO. Average age was 68.53 years, 153 males, 160 females. In alternative electromyotomy group there were 369 hips with 86 HO (23.30%), clinically relevant HO cases developed in 5.69%, 21 patients. HO in particular types: 139 cemented hips with 43 HO, uncemented 228 with 42 HO and hybrid 2 with 1 HO. Average age was 70.56y, males 171, females 198. Statistic values of HO occurence between these groups favourising the electromyotomy group were significant, such as comparing the particular Brooker grades distribution and prosthesis type (cemented, uncemented). Significant decrease was observed mainly in uncemented joint replacements and in clinically relevant grades in electromyotomy group. A novel perspective on primary prophylaxis of heterotopic hip ossification after straight femoral stem total hip replacement with engagement of modification in surgical technique so called electromyotomy is presented. Statistical analysis of results in ossification development significantly favorising modified technique in all types of prosthesis fixation, notably in uncemented prosthesis types. The main drop in counts of clinicaly relevant grades of osifications is also statistically relevant. According to these findings this surgical step is routinely implemented in our technique of straight stem implantations nowadays.